Embedded – Protocol

What is a communication protocol?

In telecommunications, a communications protocol is a system of digital rules for data exchange within or between computers. Communicating systems use well-defined formats (protocol) for exchanging messages.

  • Serial Communication Interfaces (SCI): RS-232, RS-422, RS-485 etc.
    • Synchronous Serial Communication Interface
      •  I2C, SPI, SSC and ESSI (Enhanced Synchronous Serial Interface)
  • Network
    • Ethernet,
    • LonWorks, etc.
  •  Timers
    • PLL(s),
    • Capture/Compare and Time Processing Units
  •  Discrete IO: aka General Purpose Input/Output (GPIO)
  • Fieldbuses:
    • CAN-Bus,
    • LIN-Bus,
    • PROFIBUS, etc.
  • Analog to Digital/Digital to Analog (ADC/DAC)
  • Debugging :
    • JTAG,
    • ISP,
    • ICSP,
    • BDM Port,
    • BITP and DP9 ports

Type of Communications

  1. Simplex Communication : One way communication. Receiver can’t resend data back to transmitter.
  2. Duplex Communication : Two or both way communication.
    1. Half Duplex : Two or both way communication. But Can’t exchange the data same time. Ex : Like Walkie Talkie.
    2. Full Duplex : Two or both way communication and can exchange data same time. Ex : Like Phone Call.

Methods of communication

  1. Synchronous Communication : Based on clock pulse
  2. Asynchronous Communication :No clock pulse, based upon the register configuration (Internal clock pulse)

 

Wireless Protocols Standards

  • 802.1        –    Inter connection(bridging)
  • 802.2        –    Logical link control
  • 802.3        –    Ethernet(CSMA/CD)LAN
  • 802.4        –    Token bus LAN
  • 802.5        –    Token ring LAN
  • 802.6        –    Metropolitan Area Networks (DQDB)
  • 802.7        –    Broad band TAG
  • 802.8        –    Fiber optic TAG
  • 802.9        –    Isochronous LAN
  • 802.10        –    Security
  • 802.11        –    Wireless LAN/Wi Fi
  • 802.12        –    Demand priority
  • 802.14        –    Cable modem
  • 802.15        –    Wireless personal aread network(PAN)
  • 802.15.1    –    Bluetooth
  • 802.15.3    –    Light rato wireless PAN
  • 802.15.4    –    ZigBee
  • 802.15.6    –    Body area network
  • 802.16        –    Broad band wireless(Wi max)
  • 802.17        –    Resilient Packet Ring
  • 802.18        –    Radio regulatory WG(Mobile broad band wireless access)
  • 802.19        –    Coexistence TAG
  • 802.20        –    Mobile broadband wireless
  • 802.21        –    Media independent handoff
  • 802.22        –    Wireless regional area network

Wireless Protocol

  • 6LowPAN
    • Standard: RFC6282
    • Frequency: (adapted and used over a variety of other networking media including Bluetooth Smart or (2.4GHz) or ZigBee or low-power RF (sub-1GHz)
    • Range: N/A
    • Data Rates: N/A
  •  Bluetooth
    • Standard: Bluetooth 4.2 core specification
    • Frequency: 2.4GHz (ISM)
    • Range: 50-150m (Smart/BLE)
    • Data Rates: 1Mbps (Smart/BLE)
  • GSM (Cellular)
    • Standard: GSM/GPRS/EDGE (2G), UMTS/HSPA (3G), LTE (4G)
    • Frequencies: 900/1800/1900/2100MHz
    • Range: 35km max for GSM; 200km max for HSPA
    • Data Rates (typical download): 35-170kps (GPRS), 120-384kbps (EDGE), 384Kbps-2Mbps (UMTS),
    • 600kbps-10Mbps (HSPA), 3-10Mbps (LTE)
  • GPS
  • LoRaWAN
    • Standard: LoRaWAN
    • Frequency: Various
    • Range: 2-5km (urban environment), 15km (suburban environment)
    • Data Rates: 0.3-50 kbps.
  • NFC
    • Standard: ISO/IEC 18000-3
    • Frequency: 13.56MHz (ISM)
    • Range: 10cm
    • Data Rates: 100–420kbps
  • Neul
    • Standard: Neul
    • Frequency: 900MHz (ISM), 458MHz (UK), 470-790MHz (White Space)
    • Range: 10km
    • Data Rates: Few bps up to 100kbps
  • Sigfox
    • Standard: Sigfox
    • Frequency: 900MHz
    • Range: 30-50km (rural environments), 3-10km (urban environments)
    • Data Rates: 10-1000bps
  • Thread
    • Standard: Thread, based on IEEE802.15.4 and 6LowPAN
    • Frequency: 2.4GHz (ISM)
    • Range: N/A
    • Data Rates: N/A
  • WiFi
    • Standard: Based on 802.11n (most common usage in homes today)
    • Frequencies: 2.4GHz and 5GHz bands
    • Range: Approximately 50m
    • Data Rates: 600 Mbps maximum, but 150-200Mbps is more typical, depending on channel frequency used and number of antennas (latest 802.11-ac standard should offer 500Mbps to 1Gbps)
  • ZigBee
    • Standard: ZigBee 3.0 based on IEEE802.15.4
    • Frequency: 2.4GHz
    • Range: 10-100m
    • Data Rates: 250kbps
  • Z-Wave
    • Standard: RFC6282
    • Frequency: (adapted and used over a variety of other networking media including Bluetooth Smart
    • (2.4GHz) or ZigBee or low-power RF (sub-1GHz)
    • Range: N/A
    • Data Rates: N/A

Networking Protocol

  • TCP/IP
  • HTTP
  • MQTT
  • CoAP

Wired Communication Protocols

  • Synchronous – Clock signal synchronous
    • I2C
    • SPI
  • Asynchronous – No Clock signal synchronous
    •  UART
  • BSPI
  • CAN
  • EMI
  • ENET
  • 2CUAR
  • I2S
  • Infrared
  • HDLC
  • One-Wire(1 wire)
  • RJ-45
  • RS-232
  • RS-485
  • SSI
  • USB

 


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